On March 19th,, Assistant Professor in our team, will present us some results of her recent research activities.
Title: Application-aware arbitration of I/O resources in HPC machines
I/O forwarding is a well-established and widely-adopted technique in HPC to reduce contention in the access to storage servers and transparently improve I/O performance. Rather than having applications directly accessing the shared parallel file system, the forwarding technique defines a set of I/O nodes responsible for receiving application requests and forwarding them to the file system, thus reshaping the flow of requests. The typical approach is to statically assign I/O nodes to applications depending on the number of compute nodes they use, which is not always necessarily related to their I/O requirements. Thus, this approach leads to inefficient usage of these resources.
During this talk, I will present our recent work, accepted for IPDPS 2021, that investigates arbitration policies based on the applications I/O demands, represented by their access patterns. We proposed a policy based on the Multiple-Choice Knapsack problem that seeks to maximize global bandwidth by giving more I/O nodes to applications that will benefit the most. Our approach can transparently improve global I/O bandwidth by up to 85% in a live setup compared to the default static policy. I will also discuss ongoing work about trying to predict application I/O performance with different numbers of I/O nodes.